Multimedia player frameworks have become widespread. Later versions of the most popular Internet browsers—Microsoft's Internet Explorer and Netscape's Communicator—include at least one player in the basic package. These are frameworks such as RealNetworks, Inc.'s RealPlayer™ G2 family (collectively, the “RealPlayer™”); Microsoft Corporation's Windows Media Technologies (NetShow™); Macromedia, Inc.'s Director™; Apple Computer, Inc.'s QuickTime™; and Sun Microsystems, Inc.'s Java™ Media Framework (JMF). Most of these frameworks are extensible by means of plug-ins discussed below; some, notably JMF, are extensible by means of applications built on top of the frameworks. By being extensible we mean that a particular framework supports a set of interfaces exposed for interaction with additional software modules or components.
A framework is a set of interfaces, e.g., API's and procedures, and a set of capabilities exposed for the purposes of extensibility. It need not operate on multimedia-type files, i.e., files ordered sequentially and supporting the concept of a time-line; frameworks generally need not operate on time- or otherwise-ordered data files. In the rest of this document, however, we will discuss predominantly frameworks operating on ordered data flow files. We will refer to such frameworks interchangeably as “frameworks,” “extensible frameworks,” “extensible data flow-based frameworks,” or by similar expressions; we do not imply any difference in the particular designation used, unless otherwise indicated.
Frameworks are extended by means of extensions, for example plug-ins. Plug-ins, also referred to as extension modules, are modules or components dynamically loaded at run-time. Extensible architecture and plug-ins have been used in commercial products, the RealPlayer™ and Windows Media Technologies being two instances. They also have been described in various publications. See U.S. Pat. Nos. 5,838,906 and 5,870,559. (The specifications of these patents are incorporated by reference as if fully set forth herein.) A number of companies market plug-ins specifically for extending multimedia players.